In Vivo Imaging of Dentate Gyrus Mossy Cells in Behaving Mice

Abstract

Mossy cells in the hilus of the dentate gyrus constitute a major excitatory principal cell type in the mammalian hippocampus; however, it remains unknown how these cells behave invivo. Here, we have used two-photon Ca2+ imaging to monitor theactivity of mossy cells in awake, behaving mice. We find that mossy cells are significantly more active than dentate granule cells invivo, exhibit spatial tuning during head-fixed spatial navigation, and undergo robust remapping of their spatial representations in response to contextual manipulation. Ourresults provide a functional characterization of mossy cells in the behaving animal and demonstrate their active participation in spatial coding and contextual representation.